1、 ETSI TS 102 606-3 V1.1.1 (2014-07) Digital Video Broadcasting (DVB); Generic Stream Encapsulation (GSE); Part 3: Robust Header Compression (ROHC) for IP TECHNICAL SPECIFICATION ETSI ETSI TS 102 606-3 V1.1.1 (2014-07)2Reference DTS/JTC-DVB-338-3 Keywords broadcasting, DVB ETSI 650 Route des Lucioles
2、 F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The present document can be downloaded from: http:/www.etsi.org The presen
3、t document may be made available in electronic versions and/or in print. The content of any electronic and/or print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any existing or perceived difference in contents between such version
4、s and/or in print, the only prevailing document is the print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the curr
5、ent status of this and other ETSI documents is available at http:/portal.etsi.org/tb/status/status.asp If you find errors in the present document, please send your comment to one of the following services: http:/portal.etsi.org/chaircor/ETSI_support.asp Copyright Notification No part may be reproduc
6、ed or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm except as authorized by written permission of ETSI. The content of the PDF version shall not be modified without the written authorization of ETSI. The copyright and the foregoing restriction e
7、xtend to reproduction in all media. European Telecommunications Standards Institute 2014. European Broadcasting Union 2014. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM and LTE are Trade Marks of ETSI regi
8、stered for the benefit of its Members and of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI ETSI TS 102 606-3 V1.1.1 (2014-07)3Contents Intellectual Property Rights 4g3Foreword . 4g3Modal verbs terminology 4g3Introduction 5g31
9、 Scope 6g32 References 6g32.1 Normative references . 6g32.2 Informative references 6g33 Abbreviations . 6g34 Header compression and decompression for IP streams 7g34.1 ROHC module 7g34.1.1 Header compression algorithms 7g34.1.2 ROHC parameters . 8g34.1.3 ROHC rules of operation 8g34.2 Adaptation Mod
10、ule . 8g34.2.1 Compressor side 8g34.2.2 Decompressor side 8g35 Transport in DVB-GSE 9g3History 10g3ETSI ETSI TS 102 606-3 V1.1.1 (2014-07)4Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these
11、essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest up
12、dates are available on the ETSI Web server (http:/ipr.etsi.org). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web serv
13、er) which are, or may be, or may become, essential to the present document. Foreword This Technical Specification (TS) has been produced by Joint Technical Committee (JTC) Broadcast of the European Broadcasting Union (EBU), Comit Europen de Normalisation ELECtrotechnique (CENELEC) and the European T
14、elecommunications Standards Institute (ETSI). NOTE: The EBU/ETSI JTC Broadcast was established in 1990 to co-ordinate the drafting of standards in the specific field of broadcasting and related fields. Since 1995 the JTC Broadcast became a tripartite body by including in the Memorandum of Understand
15、ing also CENELEC, which is responsible for the standardization of radio and television receivers. The EBU is a professional association of broadcasting organizations whose work includes the co-ordination of its members activities in the technical, legal, programme-making and programme-exchange domai
16、ns. The EBU has active members in about 60 countries in the European broadcasting area; its headquarters is in Geneva. European Broadcasting Union CH-1218 GRAND SACONNEX (Geneva) Switzerland Tel: +41 22 717 21 11 Fax: +41 22 717 24 81 The Digital Video Broadcasting Project (DVB) is an industry-led c
17、onsortium of broadcasters, manufacturers, network operators, software developers, regulatory bodies, content owners and others committed to designing global standards for the delivery of digital television and data services. DVB fosters market driven solutions that meet the needs and economic circum
18、stances of broadcast industry stakeholders and consumers. DVB standards cover all aspects of digital television from transmission through interfacing, conditional access and interactivity for digital video, audio and data. The consortium came together in 1993 to provide global standardisation, inter
19、operability and future proof specifications. The present document is part 3 of a multi-part deliverable covering the Digital Video Broadcasting (DVB); Generic Stream Encapsulation (GSE), as identified below: Part 1: “Protocol“; Part 2: “Logical Link Control (LLC)“; Part 3: “Robust Header Compression
20、 (ROHC) for IP“. Modal verbs terminology In the present document “shall“, “shall not“, “should“, “should not“, “may“, “may not“, “need“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
21、provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 102 606-3 V1.1.1 (2014-07)5Introduction As introduced in TS 102 606-1 1, the Generic Stream Encapsulation (GSE) protocol is a link layer which provides multiplexing mechanisms th
22、at make it possible for several network protocols (for example IP, IPX, Decnet, and Appletalk) to coexist within a multipoint network and to be transported over the same network media. GSE is designed to be deployed across all DVB broadcast bearers which provide a Generic Stream mode. Due to the use
23、 of GSE on broadcast bearers, making efficient use of the available link capacity is an important factor for a cost effective deployment. An additional. special property of broadcast links is the possible presence of non-negligible error rates and long round-trip times. Other existing header compres
24、sion schemes generally do not perform well when used over links with these properties. To complement the payload compression offered by some application layer protocols, and enable the use over broadcst links, the present document defines a highly robust and efficient header compression scheme for R
25、TP/UDP/IP (Real-Time Transport Protocol, User Datagram Protocol, Internet Protocol), UDP/IP, and ESP/IP (Encapsulating Security Payload) headers. While the IETF RFC documents RFC 5795 3, RFC 3095 4, RFC 4815 5, and RFC 3843 6 define a header compression scheme for unidirectional links, they make no
26、specific provisions for use on broadcast bearers. TS 102 606-2 2 defines a link layer mechanism to supply the additional information needed for using header compression on DVB broadcast bearers. ETSI ETSI TS 102 606-3 V1.1.1 (2014-07)61 Scope The present document specifies a Robust Header Compressio
27、n (ROHC) method to be used on DVB streams where the Generic Stream Encapsulation (GSE) TS 102 606-1 1 protocol is used as the link layer for IP. 2 References References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific refer
28、ences, only the cited version applies. For non-specific references, the latest version of the referenced document (including any amendments) applies. Referenced documents which are not found to be publicly available in the expected location might be found at http:/docbox.etsi.org/Reference. NOTE: Wh
29、ile any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee their long term validity. 2.1 Normative references The following referenced documents are necessary for the application of the present document. 1 ETSI TS 102 606-1: “Digital Video Broadcasting (D
30、VB); Generic Stream Encapsulation (GSE); Part 1: Protocol“. 2 ETSI TS 102 606-2: “Digital Video Broadcasting (DVB); Generic Stream Encapsulation (GSE); Part 2: Logical Link Control (LLC)“. 3 RFC 5795: “The RObust Header Compression (ROHC) Framework“. 4 RFC 3095: “RObust Header Compression (ROHC): Fr
31、amework and four profiles: RTP, UDP, ESP, and uncompressed“. 5 RFC 4815: “RObust Header Compression (ROHC): Corrections and Clarifications to RFC 3095“. 6 RFC 3843: “RObust Header Compression (ROHC): A Compression Profile for IP“. 7 IEEE EtherType registry. Available at: http:/standards.ieee.org/dev
32、elop/regauth/ethertype/eth.txt 2.2 Informative references The following referenced documents are not necessary for the application of the present document but they assist the user with regard to a particular subject area. Not applicable. 3 Abbreviations For the purposes of the present document, the
33、abbreviations given in TS 102 606-1 1 and the following apply: CID Context IDentifier ESP Encapsulating Security Payload GSE Generic Stream Encapsulation IP Internet Protocol IR Intra-Refresh IR-DYN IR-Dynamic ETSI ETSI TS 102 606-3 V1.1.1 (2014-07)7LLC Logical Link Control ROHC RObust Header Compre
34、ssion RTP Real-time Transport Protocol 4 Header compression and decompression for IP streams Header compression for the IP Profile of DVB-GSE (Figure 1) is composed of two sub-modules: the Robust Header Compression (ROHC) module, and the Adaptation module. Header compression may be used in the IP Pr
35、ofile of DVB-GSE and, if used, shall be applied to IP streams. Figure 1: Header compression for IP streams Header decompression (Figure 2) also consists of a Robust Header Compression (ROHC) module, and an Adaptation module, but in inverse order. Figure 2: Header decompression for IP streams 4.1 ROH
36、C module The ROHC module is responsible for reduction of overhead in IP flows by compresing the headers of IP datagrams. It shall operate in the unidirectional mode (ROHC-U) as specified in RFC 5795 3, section 4.4.1 of RFC 3095 4 and as amended by RFC 4815 5. 4.1.1 Header compression algorithms The
37、ROHC framework defines multiple header compression algorithms, called profiles. Each profile is specific to the particular network layer, transport layer, or upper layer protocol combination. In DVB-GSE, only the system profiles listed in Table 1 shall be used and shall be supported by receivers. Ta
38、ble 1: ROHC profiles for DVB-GSE Profile identifier Used for Reference 0x0001 RTP/UDP/IP RFC 3095 4 and RFC 4815 5 0x0002 UDP/IP RFC 3095 4 and RFC 4815 5 0x0003 ESP/IP RFC 3095 4 and RFC 4815 5 0x0004 IP RFC 3843 6 and RFC 4815 5 ETSI ETSI TS 102 606-3 V1.1.1 (2014-07)84.1.2 ROHC parameters The ROH
39、C framework defines per channel configuration parameters that are configured in a coherent way in the compressor and decompressor to allow them to interoperate (see section 5.1.1 of RFC 3095 4). To ensure interoperability between compressors and decompressors for DVB-GSE, the following rules shall a
40、pply: a) MAX_CID: This parameter indicates the maximum CID value that is in use. The MAX_CID parameter can be inferred from the context_id field of the ROHC-U descriptor in GSE LLC, TS 102 606-2 2. b) LARGE_CIDS: The value of this booelan parameter can be inferred from the context_id field of the RO
41、HC-U descriptor in GSE LLC, TS 102 606-2 2. c) PROFILES: This value is a profile identifier (see clause 4.1.1) that indicates which profile is used by the compressor. The list of profiles is defined in clause 4.1.1. The PROFILES parameter is conveyed in the context_profile field of the ROHC-U descri
42、ptor in GSE LLC, TS 102 606-2 2. d) FEEDBACK_FOR: This parameter shall not be used. e) MRRU: Segmentation shall not be used. 4.1.3 ROHC rules of operation DVB-GSE imposes additional restriction to the operation of ROHC framework. The following rules shall apply: a) If any change in the static fields
43、 of the input IP stream is detected by the ROHC compressor, then the ROHC compressor shall perform context re-initialization (CONTEXT_REINITIALIZATION signal is triggered as described in section 6.3.1 of RFC 3095 4 and the new value of the Context ID (CID) shall be assigned to the compressed IP stre
44、am. The new CID value shall be unique for the system and be not used by any other instance of ROHC compressors operated in the system. b) Any ROHC compressor and decompressor used with DVB-GSE, shall always operate in unidirectional mode as described in RFC 3095 4. 4.2 Adaptation Module The Adaptati
45、on module conveys the necessary decompressor configuration parameters to receivers by inserting them into the ROHC-U descriptor in the LLC data (see TS 102 606-2 2); also see clause 5 for details. It thereby allows to minimize the impact of the header compression mechanism on zapping delay, and impr
46、ove the error robustness of compressed flows. 4.2.1 Compressor side The Adaptation module shall extract the static chain bytes (see section 5.7.7.1 of RFC 3095 4) from the each IR packet transmitted in the ROHC compressed data flow. After extracting the static chain bytes, each IR packet shall be co
47、nverted to an IR-DYN packet type by the Adaptation module. The newly created IR-DYN packet shall transmitted inside the ROHC compressed flow, replacing the original IR packet. The extracted static chain data shall be transmitted together with signalling data outside the ROHC compressed flow as speci
48、fied in TS 102 606-2 2. 4.2.2 Decompressor side The Adaptation module shall detect IR-DYN type packets in the ROHC compressed data flow. All IR-DYN packets from the received data flow shall be converted by the Adaptation module to IR packet type, using the corresponding static chain bytes received i
49、n the GSE LLC signalling. The newly created IR packet shall be transmitted in the ROHC compressed flow, replacing the original IR-DYN packet. ETSI ETSI TS 102 606-3 V1.1.1 (2014-07)95 Transport in DVB-GSE Protocols carried in GSE streams are identified by the Protocol Type field in the GSE header TS 102 606-1 1. GSE streams carrying ROHC-U compressed IP streams according to the present document, shall use the EtherType value assigned by IEEE 7 to Robust Header Compression according to RFC 3095 4
